JP2010093857A - Base station apparatus and mobile station apparatus in multicarrier communication - Google Patents

Abstract

An object of the present invention is to prevent complex adaptive control for a channel for performing frequency scheduling transmission when performing frequency scheduling transmission and frequency diversity transmission simultaneously in multicarrier communication.
A modulation unit (12) performs modulation processing on encoded Dch data to generate Dch data symbols. The modulation unit (22) performs modulation processing on the encoded Lch data to generate Lch data symbols. An assigning unit (103) assigns the Dch data symbol and the Lch data symbol to each subcarrier constituting the OFDM symbol, and outputs it to the multiplexing unit (104). At this time, the assigning unit (103) assigns the Dch data symbol and the Lch data symbol to each subcarrier together for each subband.
[Selection] Figure 1

Description

  The present invention relates to a base station apparatus and a mobile station apparatus in multicarrier communication.

  In recent years, in wireless communication, particularly mobile communication, various information such as images and data other than voice has been the object of transmission. In the future, it is expected that the demand for higher-speed transmission will increase further, and in order to perform high-speed transmission, wireless transmission technology that achieves high transmission efficiency by using limited frequency resources more efficiently is required. ing.

  One of the radio transmission technologies that can meet such demand is OFDM (Orthogonal Frequency Division Multiplexing). OFDM is a multicarrier transmission technology that transmits data in parallel using a large number of subcarriers, and has features such as high frequency utilization efficiency and reduced intersymbol interference in a multipath environment, and is effective in improving transmission efficiency. It is known.

  Consider using frequency scheduling transmission and frequency diversity transmission when this OFDM is used for the downlink and data for multiple radio communication mobile station devices (hereinafter simply referred to as mobile stations) is frequency multiplexed onto multiple subcarriers. (For example, refer nonpatent literature 1).

  In frequency scheduling transmission, a radio communication base station apparatus (hereinafter simply referred to as a base station) allocates subcarriers adaptively to each mobile station based on reception quality for each frequency band at each mobile station. The multi-user diversity effect can be obtained, and communication can be performed very efficiently. Such frequency scheduling transmission is mainly a method suitable for data communication when a mobile station moves at low speed. On the other hand, since frequency scheduling transmission requires feedback of reception quality information from each mobile station, frequency scheduling transmission is not suitable for data communication when the mobile station moves at high speed. Further, since frequency scheduling is usually performed for each subband obtained by blocking several adjacent subcarriers together, a very high frequency diversity effect cannot be obtained.

  In Non-Patent Document 1, a channel for performing such frequency scheduling transmission is referred to as a Localized Channel (hereinafter referred to as Lch). Conventionally, Lch is assigned in subband units or in units of a plurality of consecutive subcarriers. In general, for Lch, adaptive control such as adaptive modulation is performed for each subband (frequency axis) and for each subframe (time axis). For example, the base station adaptively controls the modulation scheme and coding rate (MCS) of Lch data symbols based on the reception quality information fed back from the mobile station in order to satisfy the required error rate.

  Non-Patent Document 1 shows an example in which one frame (10 ms) is divided into 20 subframes (1 subframe = 0.5 ms), and one or more OFDM symbols are included in one subframe. Yes.

  On the other hand, in frequency diversity transmission, since data to each mobile station is distributed and allocated to subcarriers in the entire band, a high frequency diversity effect can be obtained. Further, frequency diversity transmission does not require reception quality information from a mobile station, and is an effective method in situations where frequency scheduling transmission is difficult to apply as described above. On the other hand, since frequency diversity transmission is performed regardless of the reception quality at each mobile station, a multiuser diversity effect such as frequency scheduling transmission cannot be obtained. In Non-Patent Document 1, a channel for performing such frequency diversity transmission is referred to as a distributed channel (hereinafter referred to as Dch). Conventionally, Dch is set by an FH (Frequency Hopping) pattern over the entire band of the OFDM symbol.

R1-050604 “Downlink Channelization and Multiplexing for EUTRA” 3GPP TSG RAN WG1 Ad Hoc on LTE, Sophia Antipolis, France, 20-21 June, 2005

  Here, in Non-Patent Document 1, when performing frequency scheduling transmission and frequency diversity transmission at the same time, Dch is set by an FH pattern over the entire band of the OFDM symbol. Data symbols are assigned. For this reason, when the number of mobile stations communicating with the base station changes and the set number of Dchs changes, the resource size of 1 Lch, that is, the number of bits transmitted by Lch in one subband and one subframe changes. That is, the Lch encoding block size differs for each subframe.

  Thus, when the Lch coding block size differs for each subframe, the coding gain differs for each subframe, and the error rate achievable with a certain reception quality changes for each subframe. That is, as described in Non-Patent Document 1, when Dch is set by an FH pattern over the entire band of the OFDM symbol, the BER (Bit Error Rate) characteristic of Lch changes due to a change in the number of Dch settings. As described above, since adaptive modulation is normally performed for each subframe for Lch, if the BER characteristic of Lch changes due to a change in the number of Dch settings, the base station changes the BER characteristic. In addition, it is necessary to change the correspondence between reception quality and MCS in adaptive modulation for each subframe, and Lch adaptive control becomes complicated.

  In addition, when the Lch coding block size changes for each subframe due to a change in the number of Dch settings, the base station transmits a coding block to the mobile station that receives and decodes the Lch data symbols each time the change occurs. The size needs to be notified, and the design of the communication system becomes complicated.

  An object of the present invention is to provide a base station apparatus capable of preventing complicated adaptive control for a channel for performing frequency scheduling transmission when performing frequency scheduling transmission and frequency diversity transmission simultaneously in multicarrier communication. A mobile station apparatus is provided.

  A subband setting method according to one aspect of the present invention divides a plurality of subcarriers constituting a multicarrier signal into a plurality of subbands, and transmits the plurality of subcarriers to each of a plurality of radio communication mobile station apparatuses. Both the first subband including data and the second subband including data only for one radio communication mobile station apparatus are set.

  ADVANTAGE OF THE INVENTION According to this invention, when performing frequency scheduling transmission and frequency diversity transmission simultaneously in multicarrier communication, it can prevent that the adaptive control about the channel for performing frequency scheduling transmission becomes complicated.

The block diagram which shows the structure of the base station which concerns on Embodiment 1 of this invention. Example of subband division according to Embodiment 1 of the present invention Subband setting example (setting example 1) according to Embodiment 1 of the present invention Subband setting example (setting example 2) according to Embodiment 1 of the present invention Subband setting example (setting example 3) according to Embodiment 1 of the present invention Subband setting example (setting example 3) according to Embodiment 1 of the present invention Subband setting example (setting example 4) according to Embodiment 1 of the present invention Subband setting example (setting example 5) according to Embodiment 1 of the present invention Subband setting example (setting example 6) according to Embodiment 1 of the present invention Subband setting example (setting example 7) according to Embodiment 1 of the present invention The block diagram which shows the structure of the base station which concerns on Embodiment 2 of this invention. Subband setting example according to Embodiment 2 of the present invention Control information format according to Embodiment 2 of the present invention The block diagram which shows the structure of the base station which concerns on Embodiment 3 of this invention. Example of transmission power control in Embodiment 3 of the present invention

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(Embodiment 1)
The configuration of base station 100 according to the present embodiment is shown in FIG. Base station 100 divides a plurality of subcarriers constituting an OFDM symbol which is a multicarrier signal into a plurality of subbands, and sets Dch or Lch for each subband in the plurality of subbands.

  In base station 100, encoding / modulation sections 101-1 to 101-n including encoding section 11 and modulation section 12 for Dch data, and encoding section 21 and modulation section 22 for Lch data are provided. The modulation units 102-1 to 102-n and the demodulation / decoding units 115-1 to 115-n including the demodulation unit 31 and the decoding unit 32 are the number n of mobile stations (MS) with which the base station 100 can communicate. Only provided.

  In the encoding / modulation units 101-1 to 101-n, the encoding unit 11 performs an encoding process such as a turbo code on the Dch data # 1 to #n for each of the mobile stations # 1 to #n to perform modulation. The unit 12 performs a modulation process on the encoded Dch data to generate a Dch data symbol.

  In the encoding / modulation units 102-1 to 102-n, the encoding unit 21 performs an encoding process such as a turbo code on the Lch data # 1 to #n for each of the mobile stations # 1 to #n, and performs modulation. Unit 22 performs modulation processing on the encoded Lch data to generate Lch data symbols. The coding rate and the modulation scheme at this time follow the MCS information input from the adaptive control unit 116.

  Allocation section 103 allocates the Dch data symbol and the Lch data symbol to each subcarrier constituting the OFDM symbol according to the control from adaptive control section 116 and outputs the result to multiplexing section 104. At this time, assignment section 103 assigns Dch data symbols and Lch data symbols to each subcarrier together for each subband. That is, assigning section 103 assigns Dch data symbols to Dch subbands and assigns Lch data symbols to Lch subbands. Also, allocating section 103 assigns Dch data symbol assignment information (information indicating which mobile station Dch data symbol is assigned to which subcarrier) and Lch data symbol assignment information (which mobile station Lch data symbol is assigned to which subcarrier). Information indicating whether the carrier has been allocated) is output to the control information generation unit 105.

  Control information generation section 105 generates control information including Dch data symbol allocation information, Lch data symbol allocation information, and MCS information input from adaptive control section 116, and outputs the control information to encoding section 106.

  The encoding unit 106 performs encoding processing on the control information, and the modulation unit 107 performs modulation processing on the encoded control information and outputs the control information to the multiplexing unit 104.

  Multiplexing section 104 multiplexes control information on each data symbol input from allocation section 103 and outputs the multiplexed information to IFFT (Inverse Fast Fourier Transform) section 108. Note that the multiplexing of control information is performed, for example, for each subframe. Further, in the present embodiment, the multiplexing of control information may be either time multiplexing or frequency multiplexing.

  IFFT section 108 performs IFFT on a plurality of subcarriers to which control information and data symbols are assigned, and generates an OFDM symbol that is a multicarrier signal.

  CP (Cyclic Prefix) adding section 109 adds the same signal as the tail part of the OFDM symbol to the beginning of the OFDM symbol as a CP.

  Radio transmitting section 110 performs transmission processing such as D / A conversion, amplification and up-conversion on the OFDM symbol with the CP added, and transmits the result from antenna 111 to each mobile station.

  On the other hand, the radio reception unit 112 receives n OFDM symbols simultaneously transmitted from a maximum of n mobile stations via the antenna 111, and performs reception processing such as down-conversion and D / A conversion on these OFDM symbols. I do.

  CP removing section 113 removes the CP from the OFDM symbol after reception processing.

  An FFT (Fast Fourier Transform) unit 114 performs FFT on the OFDM symbol after CP removal, and obtains a signal for each mobile station multiplexed on the frequency axis. Here, each mobile station transmits a signal using different subcarriers or different subbands, and the reception quality information for each subband reported from each mobile station is included in the signal for each mobile station. include. Each mobile station measures reception quality for each subband, including reception SNR, reception SIR, reception SINR, reception CINR, reception power, interference power, bit error rate, throughput, MCS that can achieve a predetermined error rate, etc. Can be performed. The reception quality information may be expressed as CQI (Channel Quality Indicator), CSI (Channel State Information), or the like.

  In the demodulation / decoding units 115-1 to 115-n, the demodulation unit 31 performs modulation processing on the signal after FFT, and the decoding unit 32 performs decoding processing on the demodulated signal. Thereby, reception data is obtained. Of the received data, reception quality information for each subband is input to adaptive control section 116.

  The adaptive control unit 116 performs adaptive control on the Lch data based on the reception quality information for each subband reported from each mobile station. That is, adaptive control section 116 selects MCS that can satisfy the required error rate for encoding / modulation sections 102-1 to 102-n based on reception quality information for each subband. MCS information is output every time, and the allocation unit 103 uses a scheduling algorithm such as the Max SIR method or the Proportional Fairness method to assign which subchannel each of the Lch data # 1 to #n to each subband. Frequency scheduling is performed to determine whether to assign to a carrier. Further, adaptive control section 116 outputs MCS information for each subband to control information generation section 105.

Next, a setting example of subbands in the present embodiment will be described. In the following description, as shown in FIG. 2, as an example, one OFDM symbol is composed of subcarriers f _{1 to} f ₇₂ and these subcarriers are equally divided into subbands (SB) 1 to 12. I will give you a description. Therefore, one subband includes six subcarriers. Also, it is assumed that one subframe includes 6 OFDM symbols. In addition, although the following subband setting is described as being performed in the allocation unit 103 in advance, the present invention is not limited to this, and the subband setting may be changed for each subframe.

<Subband setting example 1 (FIG. 3)>
In this setting example, as shown in FIG. 3, subbands 1, 4, 7, and 10 are set as Dch subbands, and subbands 2, 3, 5, 6, 8, 9, 11, and 12 are set to Lch. Set to subband for. That is, in subbands 1 to 12, Dch subbands (subbands that accommodate only Dch) are set at regular intervals and are periodically arranged.

  Here, since frequency scheduling is performed in units of subbands for Lch, each subband for Lch includes an Lch data symbol for only one mobile station. That is, one Lch for one mobile station is constituted by one subband. Therefore, in the example shown in FIG. 3, eight Lchs of Lch 1 to 8 are set.

  On the other hand, since it is necessary to perform frequency diversity transmission for Dch, each of Dch subbands 1, 4, 7, and 10 includes Dch data symbols for a plurality of mobile stations. In the example shown in FIG. 3, each Dch subband includes Dch data symbols for six mobile stations. That is, in each Dch subband, a plurality of Dchs of a plurality of mobile stations are frequency-multiplexed. Therefore, in the example shown in FIG. 3, each of Dch 1 to 6 for each of six mobile stations is configured by four Dch subbands.

  In this setting example, 8 Lch and 6 Dch are frequency-multiplexed in this way.

As described above, in the present embodiment, Dch is not set by the FH pattern over the entire band f _{1 to} f ₇₂ of the OFDM symbol, but is set in units of subbands. Therefore, the Dch data symbol is included in the Lch subband. Will no longer be assigned. Therefore, even if the number of mobile stations communicating with base station 100 changes and the number of Dch settings changes, the coding block size of each Lch is kept constant at “1 subband × 1 subframe”. Therefore, according to the present embodiment, it is possible to prevent the adaptive control for Lch from becoming complicated when frequency scheduling transmission for Lch and frequency diversity transmission for Dch are performed simultaneously. Also, even if the number of Dch settings changes, the encoding block size of each Lch is kept constant at “1 subband × 1 subframe”, so that notification of the encoding block size to the mobile station becomes unnecessary. The communication system design is simplified.

<Subband setting example 2 (FIG. 4)>
Since the frequency scheduling transmission is not suitable for the mobile station moving at high speed as described above, the base station 100 transmits data using Dch of Lch and Dch to the mobile station moving at high speed. . Therefore, in this setting example, the number of Dch settings is varied for each cell according to the number of mobile stations that move at high speed (mobile stations whose moving speed exceeds a threshold value). That is, as shown in FIG. 4, the number of Dch settings is increased as the number of mobile stations moving at high speed increases. In FIG. 3, 8 Lch and 6 Dch are frequency-multiplexed, whereas in FIG. 4, subbands 1, 2, 4, 5, 7, 8, 10, and 11 are subchannels for Dch. By setting the subbands 3, 6, 9, and 12 as subchannels for Lch, four Lch and 12 Dch are frequency-multiplexed. As a result, as the number of mobile stations moving at high speed increases, the number of mobile stations to which the base station 100 can transmit data using Dch can be increased.

<Subband setting example 3 (FIGS. 5 and 6)>
In the plurality of subbands 1 to 12 in one OFDM symbol, the smaller the interval 41 between the plurality of Dch subbands including the Dch data symbol for the same mobile station, the smaller the Dch subbands constituting one Dch. Since the number increases, the frequency diversity effect increases. Therefore, in this setting example, in a propagation environment such as a macro cell where the delay dispersion of the propagation path is large (that is, fading fluctuation in the frequency axis direction of the propagation path is fast and the coherent bandwidth of the propagation path is narrow), a large frequency diversity effect 5, the interval 41 is set small as shown in FIG. 5, and the delay dispersion of the propagation path is small such as a microcell (that is, the coherent band of the propagation path is slow in fading fluctuation in the frequency axis direction of the propagation path). In a propagation environment having a wide width, it is difficult to obtain a frequency diversity effect in the first place. Therefore, the interval 41 is set large as shown in FIG. That is, in this setting example, the setting interval of the plurality of Dch subbands including Dch data symbols for the same mobile station is reduced as the delay dispersion of the propagation path increases.

  Further, when the interval 41 is set small as shown in FIG. 5 in order to make the data amount of Dch data transmitted to each mobile station by one OFDM symbol constant regardless of the size of the set interval 41, for each Dch When the number of subcarriers allocated to one mobile station in the subband is reduced to increase the number of mobile stations to be frequency-multiplexed and the interval 41 is set large as shown in FIG. 6, each Dch subband The number of subcarriers allocated to one mobile station is increased to reduce the number of frequency-multiplexed mobile stations. Specifically, the number of mobile stations frequency-multiplexed in each Dch subband is 6 in the case of FIG. 5 and 3 in the case of FIG. That is, in this setting example, as the delay dispersion of the propagation path increases, the interval 41 is reduced and the number of mobile stations frequency-multiplexed in each Dch subband is increased.

  Thus, in this setting example, when the delay dispersion of the propagation path is small, as shown in FIG. 6, while increasing the interval 41, the number of mobile stations frequency-multiplexed in each Dch subband is reduced. To do. Therefore, according to this setting example, when the delay dispersion of the propagation path is small (in the case of FIG. 6), the increase / decrease in the number of Dch is smaller than when the delay dispersion of the propagation path is large (the case of FIG. 5). Can be done in units. Specifically, in the case of FIG. 5, it is necessary to increase / decrease Dch in units of six, whereas in FIG. 6, it is possible to increase / decrease Dch in units of three. Thus, according to this setting example, when the delay dispersion of the propagation path is small, the ratio between the number of Lch and the number of Dch can be set more flexibly than when it is large.

<Subband setting example 4 (FIG. 7)>
In setting examples 1 to 3, a plurality of Dchs are frequency-multiplexed in each Dch subband, whereas in this setting example, a plurality of Dchs are time-multiplexed in each Dch subband as shown in FIG. That is, in this setting example, a plurality of mobile stations are time-multiplexed in the Dch subband. Thereby, the frequency diversity effect is obtained in Dch. In addition, since each mobile station only needs to perform reception processing such as FFT only in the time zone assigned to the mobile station, the power consumption of the mobile station can be reduced. In addition, the base station 100 transmits the Dch data symbol allocation information earlier than other control information such as MCS information, or performs simple encoding on the Dch data symbol allocation information, so that the mobile station Since it becomes possible to know the time zone in which the Dch is assigned to the own station earlier and to stop the reception processing earlier, the power consumption of the mobile station can be further reduced.

<Subband setting example 5 (FIG. 8)>
In this setting example, as shown in FIG. 8 in addition to setting example 4 (FIG. 7), the positions at which each Dch is time-multiplexed in a plurality of Dch subbands are made different from each other. That is, in this setting example, the time multiplexing positions of the plurality of mobile stations are made different from each other in the plurality of Dch subbands. Thereby, with respect to Dch, a diversity effect can be obtained not only in the frequency axis direction but also in the time axis direction. In addition, when the pilot signal is arranged before and after each subframe, a portion with a close channel estimation accuracy close to the pilot signal and a portion with a channel estimation accuracy far from the pilot signal are mixed in each subband. The channel estimation accuracy of each Dch can be made equal to each other by making the positions at which each Dch is time multiplexed in a plurality of Dch subbands as in the setting example.

<Subband setting example 6 (FIG. 9)>
In this setting example, as shown in FIG. 9, in each Dch subband, Dch data symbols to each mobile station are frequency hopped. As a result, it is possible to obtain a diversity effect with respect to fluctuations in the time axis direction and the frequency axis direction within each Dch subband.

<Subband setting example 7 (FIG. 10)>
In this setting example, as shown in FIG. 10, the setting positions of the Dch subbands in subbands 1 to 12 are changed for each subframe. Thereby, the frequency diversity effect regarding Dch can be further enhanced. Also, according to this setting example, a subband with high reception quality at the mobile station is not continuously used as Dch, that is, a subband with low reception quality at the mobile station is continuously used as Lch. Therefore, the Lch throughput can be improved.

  The subband setting examples 1 to 7 in the present embodiment have been described above.

  Thus, according to the present embodiment, when performing frequency scheduling transmission on Lch and frequency diversity transmission on Dch simultaneously, Dch or Lch is set for each subband, so that adaptive control for Lch is complicated. Can be prevented. Also, even if the number of Dch settings changes, the encoding block size of each Lch is kept constant at “1 subband × 1 subframe”, so that notification of the encoding block size to the mobile station becomes unnecessary. In addition, since the Dch subbands are set at regular intervals and periodically arranged, there is no need to notify the mobile station of the position information of the Dch subbands. Therefore, according to the present embodiment, the design of the communication system is simplified.

  The interval between the Dch subbands is not necessarily constant, and the above-described effect can be obtained if the interval is set in advance.

  In the above description, Dch data symbol allocation information and Lch data symbol allocation information are input from allocation section 103 to control information generation section 105. These allocation information is received from adaptive control section 116 and control information generation section 105. May be entered directly into. In this case, MCS information for each subband, Dch data symbol allocation information, and Lch data symbol allocation information are input from allocation section 103 to control information generation section 105.

(Embodiment 2)
The base station according to the present embodiment is different from Embodiment 1 in that the Dch subband is made different for each mobile station according to the magnitude of the delay dispersion of the propagation path for each mobile station.

  FIG. 11 shows the configuration of base station 200 according to the present embodiment. In FIG. 11, the same components as those in the first embodiment (FIG. 1) are denoted by the same reference numerals, and description thereof is omitted.

  In the base station 200, a signal for each mobile station obtained by the FFT unit 114 is input to the propagation path fluctuation measurement unit 201. The propagation path fluctuation measurement unit 201 uses the pilot signal included in the signal for each mobile station to measure the magnitude of the propagation path fluctuation in the frequency axis direction for each mobile station, that is, the delay dispersion of the propagation path for each mobile station. The size is measured and output to the allocation unit 103.

  The allocating unit 103 allocates Dch data symbols for each mobile station to each Dch subband as follows according to the delay dispersion of the propagation path for each mobile station.

  That is, in the present embodiment, as shown in FIG. 12, Dch subbands are classified into subbands having a large setting interval 41 and subbands having a small setting interval 41. That is, both a Dch subband with a large setting interval 41 and a Dch subband with a small setting interval 41 are set in one OFDM symbol.

  Here, the setting interval 41 is the same as the setting interval 41 in the subband setting example 3 of the first embodiment. Similarly to the subband setting example 3, in this embodiment, in order to make the data amount of Dch data transmitted to each mobile station by one OFDM symbol constant regardless of the size of the setting interval 41, FIG. As shown, in the Dch subband with a small setting interval 41, since the number of Dch subbands is large, the number of subcarriers allocated to one mobile station is reduced to increase the number of frequency-multiplexed mobile stations. In the Dch subband having a large setting interval 41, since the number of Dch subbands is small, the number of subcarriers allocated to one mobile station is increased to reduce the number of frequency-multiplexed mobile stations.

  Allocation section 103 allocates Dch data symbols for mobile stations having a small delay dispersion of the propagation path to subbands for Dch (subbands 1 and 7) having a large setting interval 41 in subbands 1 to 12, and delays of the propagation path Dch data symbols for mobile stations with large dispersion are allocated to Dch subbands (subbands 2, 5, 8, 11) having a small setting interval 41. The allocation unit 103 determines whether the delay dispersion of the propagation path is small or large for each mobile station by comparing the value of the delay dispersion of the propagation path for each mobile station with a threshold value.

  In this way, in this embodiment, a plurality of Dch subbands suitable for the propagation path environment for each mobile station are set in one OFDM symbol, so that a necessary and sufficient frequency diversity effect is obtained for each mobile station. be able to.

  Next, the format of the control information according to this embodiment will be described. The control information generation unit 105 in the base station 200 generates control information according to the format shown in FIG. In the format shown in FIG. 13, 'MS-ID' is set to the ID of the mobile station that is the data symbol transmission destination, 'Channel partition' is set to partition information indicating either Dch or Lch, and 'Subband The “number” is set to the Dch subband number or the Lch subband number, and the “MCS information” is set to the MCS information of each subband. In addition, in addition to the above-described classification information, an interval between Dch subbands may be set in the “channel classification”. For example, the control information generation unit 105 selects any one of “Lch”, “Dch with 2 subband intervals”, “Dch with 3 subband intervals”, and “Dch with 6 subband intervals” as the “channel classification”. You may select and set one.

  Then, the control information generated in this way is time-multiplexed by the multiplexing unit 104 at the head of the subframe as shown in FIG. 12, and transmitted to all mobile stations as SCCH (Shared Control Channel) control data. The That is, in the present embodiment, the setting results of the Dch subband and the Lch subband in subbands 1 to 12 are notified to each mobile station using one control information having a format common to all mobile stations. .

  As described above, in this embodiment, the control information having a format common to all mobile stations is used to notify each mobile station of the setting results of the Dch subband and the Lch subband at the same time. Even if the number of Lchs changes for each subframe, control information can be transmitted without consuming data symbol transmission resources. Also, since one control information format common to Dch and Lch is used, the design of the communication system is simplified.

  In the present embodiment, the base station 200 measures the magnitude of propagation path fluctuation of each mobile station. However, each mobile station measures the magnitude of propagation path fluctuation of its own station, and the measurement result. May be reported to the base station 200.

  Also, the format of the control information shown in FIG. 13 can be used in the first embodiment. In this case, division information indicating either Dch or Lch is set in the “channel division”.

(Embodiment 3)
The base station according to the present embodiment is different from Embodiment 1 in that transmission power control is performed for each subband.

  One of techniques for reducing interference between cells is a technique called Interference Coordination. In Interference Coordination, base stations in each cell perform resource allocation in cooperation, and base stations in each cell perform transmission power control in cooperation, thereby reducing interference between cells. In this embodiment, this interference coordination is applied to the first embodiment.

  The configuration of base station 300 according to the present embodiment is shown in FIG. In FIG. 14, the same components as those in Embodiment 1 (FIG. 1) are denoted by the same reference numerals, and description thereof is omitted.

  In base station 300, transmission power control section 301 performs transmission power control of Dch data symbols and Lch data symbols for each subband. Specifically, base stations 300 of cells adjacent to each other perform transmission power control as shown in FIG. That is, base station 300 of cell 1 sets transmission power in order of large, medium, small, large, medium, small,... The base station 300 of the cell 2 sets the transmission power in the order of medium, small, large, medium, small, large,. Also, the base station 300 of the cell 3 sets transmission power in the order of small, large, medium, small, large, medium,. The transmission power of large, medium and small is, for example, transmission power “medium” as a reference (0 dB), transmission power “large” is transmission power 5 dB higher than the reference, and transmission power “small” is 5 dB from the reference. Use low transmission power. In this way, by making the transmission powers of the same subbands different between cells, interference coordination can be realized and interference between cells can be reduced.

  Conventionally, since it is necessary to perform interference coordination between Dch or Lch, it is necessary to make the number of Dch and the number of Lch the same between cells. On the other hand, when the Dch subband and the Lch subband are set as described in the first embodiment, even if the number of Dch and the number of Lch are freely set in each cell, as shown in FIG. Interference Coordination can be realized.

  Further, conventionally, since it was necessary to perform interference coordination between Dch, it was not possible to set Dch to “high” transmission power in all adjacent cells. On the other hand, when the Dch subband is set as described in the first embodiment, the Dch can be set to “high” transmission power in all adjacent cells as shown in FIG.

  The embodiments of the present invention have been described above.

  In each of the above embodiments, the signal received by the base station (that is, the signal transmitted by the mobile station on the uplink) has been described as being transmitted using the OFDM method. You may transmit by transmission systems other than OFDM systems, such as a CDMA system.

  Further, in each of the above embodiments, adaptive modulation is performed only on Lch, but adaptive modulation may be performed on Dch as well.

  Lch is a frequency scheduling channel. Dch is sometimes called a frequency diversity channel.

  Also, the mobile station may be referred to as UE, the base station apparatus as Node B, and the subcarrier as tone. A subband may also be referred to as a subchannel, a subcarrier block, a resource block, or a chunk. The CP may also be referred to as a guard interval (GI).

  Further, although cases have been described with the above embodiment as examples where the present invention is configured by hardware, the present invention can also be realized by software.

  Each functional block used in the description of each of the above embodiments is typically realized as an LSI which is an integrated circuit. These may be individually made into one chip, or may be made into one chip so as to include a part or all of them. The name used here is LSI, but it may also be called IC, system LSI, super LSI, or ultra LSI depending on the degree of integration.

  Further, the method of circuit integration is not limited to LSI's, and implementation using dedicated circuitry or general purpose processors is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI, or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

  Furthermore, if integrated circuit technology comes out to replace LSI's as a result of the advancement of semiconductor technology or a derivative other technology, it is naturally also possible to carry out function block integration using this technology. Biotechnology can be applied.

  This specification is based on Japanese Patent Application No. 2005-321110 of an application on November 4, 2005. All this content is included here.

The present invention can be applied to a mobile communication system and the like.

Claims (5)

An arrangement unit that divides and arranges data for one mobile station in two resource blocks among a plurality of resource blocks formed by dividing a plurality of continuous subcarriers in the frequency domain;
A transmission unit for transmitting the data using the plurality of blocks;
A base station apparatus. The arrangement unit arranges data for one mobile station in one resource block other than the two resource blocks among the plurality of resource blocks.
The base station apparatus according to claim 1. The same number is assigned to the data for the one mobile station,
The base station apparatus according to claim 1 or 2. Each of the plurality of resource blocks includes the same number of the subcarriers.
The base station apparatus in any one of Claim 1 to 3. A receiving unit that receives the data transmitted from the base station apparatus according to any one of claims 1 to 4,
A mobile station apparatus.

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